Diesels don't mix air with the fuel in any way like gas (spark ignition)
engines. They always run with more air than is needed for the fuel to
burn completely. The combustion chamber is full of air, compressed to oh,
19:1, 21:1 or some such, and then the fuel is sprayed in. [Direct
gasoline injection is a new thing on the market.]
Severely restricted intake, such as from a filthy air cleaner, reduces
the amount of air, lowers its pressure, resulting in lower compression
peak pressure. If the compression is marginal to start with, this may
cause poor ignition.
The intermittent stalling and failure to start sounds more like a fuel
problem. My Ford diesel tractor would start, run for a few minutes, then
die. Turned out to have clogged fuel filters.
Al